The invention generally relates to axial flow fans for use in cooling systems. The invention relates particularly to a light-weight and high efficiency axial flow fan.
An axial flow fan may be used to produce a flow of cooling air through the heat exchanger components of a vehicle. For example, an airflow generator used in an automotive cooling application may include an axial flow fan for moving cooling air through a liquid-to-air heat exchanger such as an engine radiator, condenser, intercooler, or combination thereof. The required flow rate of air through the fan and change in pressure across the fan vary depending upon the particular cooling application.
To provide adequate cooling, a fan should have performance characteristics which meet the flow rate and pressure rise requirements of the particular automotive application. For example, some applications impose low flow rate and high pressure rise while other applications impose high flow rate and low pressure rise requirements. The fan must also meet the dimensional constraints imposed by the automotive engine environment.
Accordingly, there is a need to provide an improved fan for moving air with high efficiency, low solidity and low weight which has performance characteristics meeting the requirements imposed by various automotive applications.
An object of the invention is to fulfill the need referred to above. In accordance with the principles of the present invention, this objective is achieved by providing an axial flow fan for producing airflow through an engine compartment of a vehicle. The fan includes a hub rotatable about an axis; an annular band concentric with the hub and spaced radially outward from the hub; seven fan blades distributed circumferentially around the hub and extending radially from the hub to the annular band. Each blade has specific parameters defined by:
r, the non-dimensional radius from the rotational axis (r=R/Rtip with R being the radius from the rotational axis and Rtip being the radius from the rotational axis at the blade tip),
"xgr", the stagger angle of the blade at the radial distance r,
xcex8, the camber angle of the blade at the radial distance r,
"sgr", the solidity C/S, with C being chord length and S being the circumferential blade spacing at the radial distance r,
c, the non-dimensional chord length (C/Rtip) of the blade at the radial distance r,
t, the non-dimensional thickness (T/C where T is the actual thickness at R) of the blade at radius r,
xcex9, the skew angle of the blade at the radial distance r calculated at 30% chord where the skew at the hub radius is defined as zero skew, and
dH/dR, the slope of the dihedral measured at r.
Other objects, features and characteristics of the present invention, as well as the methods of operation and the functions of the related elements of the structure, the combination of parts and economics of manufacture will become more apparent upon consideration of the following detailed description and appended claims with reference to the accompanying drawings, all of which form a part of this specification.